1. Field of the Invention
The present invention relates to a cement bonded wood chip product, a resin bonded wood chip product, a simulated wood product and manufacturing methods thereof utilizing as raw material pulverized powders obtained from recycled building members.
2. Description of Related Art
Conventionally, a simulated wood product resembling natural wood in many aspects including touch-feeling, has been manufactured by mixing pulverized powders obtained from pulverized cellulose materials with resin and the like which are then molded into desired shape by extrusion or injection molding. The above mentioned cellulose materials have been obtained from remains or sawdust of wooden materials used in the building industry. However, it has become very desirable from the standpoint of effective use of resources and environmental protection, to reuse once used building boards and the like as raw material by pulverizing them.
FIG. 2 is an illustration showing outline of a conventional method of manufacturing a simulated wood product utilizing recycled building members as raw material.
In the conventional method of manufacturing a simulated wood molding, components used for a building structure have been collected by separating them into recycled wooden members made of wooden materials and recycled resinous members made of resinous materials when a building is to be renewed. Separation work may be conducted manually or by a process which makes use of the differences in the specific gravity of materials, for instance, by way of floating the materials in a liquid. Recycled wood members and recycled resinous members are then processed on separate production lines up to a weighing process.
More specifically, all recycled wooden members are first crushed in a crushing process by a hammer mill and the like.
Next, at a weighing process, crushed wooden members are weighed to be a predetermined weight.
On the other hand, recycled resinous members are crushed by a hammer mill and the like in a crushing line different from that of the wooden members.
Next, at the pellet manufacturing process, resinous members, which have been crushed in the crushing process, are melted and the melted material is then molded into pellets by extrusion. The resinous member is crushed before the melting process because it is inconvenient to have the members in their original recycled forms in the melting process and also in order to improve the efficiency of the melting operation. Further, the reason for making the pellets is because it is advantageous for facilitating a dehydration process which is necessary prior to the molding since pellets absorb less moisture than in the originally crushed form. It is also more easily manageable as it does not disperse in the air. The pellets are granulated into the form of a sphere, a cylinder or a prism with a side length equal to 2 mm to 5 mm.
Next, in a weighing process, the pellets obtained in the pellet manufacturing process are weighed to a predetermined value. Next, in a mixing and kneading process, the weighed recycled wooden members and weighed pellets of recycled crushed resinous members are mixed and kneaded to be blended evenly.
Next, in a molding process, a predetermined pressure is applied in a predetermined temperature to the resultant mixture from the mixture and kneading process and molded into desired shapes either by extrusion or injection by means of a molding machine.
Through this process, a product with a proper ratio of wooden members and resinous members can be obtained.
Furthermore, in the above mentioned conventional manufacturing method, only predetermined weight is respectively measured to keep a definite mixing ratio of recycled wooden members and recycled resinous members in each of the weighing process. In other words, when materials of 200 kg are to be produced with a 1 to 1 weight-mixing ratio of the both members, 100 kg of recycled wooden members and 100 kg of recycled resinous members have to be weighed at each weighing process. Subsequently, both members are dispensed into a mixing mill and the like and kneaded together.
However, the above mentioned conventional method of manufacturing a simulated wood product has posed a first problem that, since the recycled wooden members and recycled resinous members had to be processed on independent production lines up to a weighing process and then mixed together, two similar lines are needed and further double space for installing the processing line as well as the number of machinery, such as pulverizing machines and the like, are required. And, in addition, more supervisors have to be provided for each production line, giving rise to more amount of labor.
Moreover, it posed a second problem that when one single pulverizing machine is used and the pulverizing process of recycled wooden members and recycled resinous member are executed by staggering the pulverizing time, time required for the pulverization will be doubled, necessitating cleaning operations at the time of switching over of the operations, which results in decrease in efficiency of the operation.
Furthermore, in the weighing process of the conventional manufacturing process, only the recycled wooden members and recycled resinous members have been weighed respectively in order to keep the mixing ratio constant. However, a mixing machine, such as a mixing mill, does not have a fixed weight but the permissible weight has a certain range which makes it unnecessary to limit the weight to a specific value if it is kept within this range. It is thus possible to obtain a uniform mixture when mixture ratio of recycled wooden members and recycled resinous members can be set at a certain value. Consequently, the conventional weighing process posed a third problem that it is necessary to weigh both of the members to a predetermined weight which necessitates more labor.